Prior to 1968, vehicle safety belts were generally considered to be optional equipment, meaning that a consumer would either have to order a vehicle with safety belts installed or attempt to locate a vehicle at a dealership that included safety belts. However, on Jan. 1, 1968, United States federal law required that all vehicles (except buses) be fitted with safety belts in all designated seating positions (Title 49 of the United States Code, Chapter 301, Motor Vehicle Safety Standard). Since that date, most states have passed laws regarding required safety belt (alternately referred to throughout as a seat belt) usage for children and/or different size adults. Additionally, federal law now requires certain passenger buses to have seat belt assemblies whose lap belt assembly can be used to tightly secure a child restraint system. Since passage of these laws, prior methods and systems are still being utilized with the same essential components in essentially the same configuration, even though those configurations are not always functional, safe, and comfortable for seat occupants of varying size, height, and age. There currently does not exist a seat belt system that successfully and automatically secures people of varying ages and sizes.
Prior methods and systems utilized in multi-point seat belt systems, e.g., 3-point seat belts, place a belt retractor in proximity to the seat, either fixed to the vehicle or to the seat at a point below the occupant or in the bottom of the seat. These methods and systems additionally utilize a fixed pillar loop or D-ring element near the seat occupant's shoulder as an anchor point for the seat belt (webbing) extending from the belt retractor. The belt additionally passes through a standard tongue shaped metal plate (“metal tongue”) (typically an element that moves freely along the webbing) and is fixed at its end to a point at or near the seat bottom, i.e., a first lower anchor point. To secure the occupant, the webbing diagonally passes across the upper torso of the occupant and across the lower portion of the occupant, with the metal tongue being inserted into a locking device that retains the metal tongue (until the occupant presses a release mechanism), creating a second lower anchor point. Due to the fixed nature and location of these anchor points, prior methods and systems do not allow for easy repositioning of the webbing/shoulder belt across the shoulder and upper torso of an occupant. In other words, the prior methods and systems often utilize the same webbing/belt positioning for both a larger adult and a small child. For those methods and systems that permit adjustment, those adjustments must be accomplished manually via height adjusters which are attaching to the vehicle or an edge of the seat. However, if a younger seat occupant (or a parent or caregiver of the younger seat occupant) fails to manually adjust the height properly, the seat belt may present a grave danger to the seat occupant in the event of a vehicle accident, as the belt may pass too close to their neck.
In the prior 3-point systems, the D-ring are sometimes attached to a vertical height adjuster, which is fastened or otherwise secured to the vehicle at point far above an adult's shoulder. As noted above, this placement may prove fatal for children or smaller adults, e.g., the belt passes too close to their neck. For example, U.S. Pat. No. 5,609,367 utilizes a second D-ring/pillar loop/webbing guide connected to a height adjuster, below a first D-ring, allowing the repositioning of the shoulder belt across the upper torso of the occupant. Since the height of the second webbing guide has to be manually adjusted, which results in potential danger to smaller seat occupants as noted above. U.S. Pat. No. 6,846,020 describes two webbing deflection points, both fastened to the seat. Both deflection points are fixed within the seat, requiring them to be manually be adjusted or moved. As noted above, the manual nature of these adjustments presents a grave danger to smaller seat occupants. Additionally, the described configuration creates a substantial amount of friction on the webbing.
In the prior 3-point systems, a standard metal tongue is used that moves freely along the webbing, which is then inserted into a locking device. A 3-point seat belt system with this metal tongue does not allow for the lap belt section of a prior seat belt assembly to tightly secure a child restraint system, which is now required by federal law for certain newly manufactured passenger buses. New seat belt systems have been designed to satisfy this law, but these systems utilize a unique retractor that is not only more expensive, but also larger and therefore hard to fit in the seat back without making the seat back wider, which often reduces the number of seat rows that fit in the bus. These retractors switch to a locking mode by pulling all of the webbing out of the retractor, which is not always understood by occupants. Additionally, due to their larger size, they must be placed in the bottom of the seat or outside of the seat, creating a longer webbing path and adding significant friction to the seat belt system. This significant friction makes the seat belt tough to use, and requires a stronger spring in the retractor to overcome the friction, creating higher retraction forces and therefore significant pressure on the occupant's chest and discouraging the use of the seat belt due to discomfort. When oversized adults use the prior 3-point systems, often there is not enough webbing in the retractor to secure them. Even high capacity retractors designed to hold more webbing for larger adults are larger and often do not fit in the seat back, especially in the top part of the seat back where it is most desired to have a narrow profile. Placing the large retractor at the bottom of the seat or below the occupant, adds significant friction, making the seat belt tough to use, and requires a stronger spring in the retractor to overcome the friction, creating higher retraction forces and therefore significant pressure on the occupant's chest and discouraging the use of the seat belt due to discomfort.
Despite advances in technology and regulations, current 3-point seat belt safety systems still fail to properly fit and protect variously-sized seat occupants automatically. For smaller seat occupants, including children, at best, modern technology introduced additional, manual steps that, if not followed every time, presents a greater danger to the seat occupant. For younger children requiring child safety restraints, prior 3-point safety belt designs cannot properly secure child safety restraints in buses, and existing 3-point seat belts cannot reasonably be adapted to do so. For very large adults, current safety belts often do not have enough webbing capacity, even with high-capacity retractors.